Numerous different concepts and approaches for operating elements are known for operating and controlling industrial trucks. For example, a control element for an industrial truck is known from DE 10 2013 012 176 that has two operating levers and at least one switch arranged therebetween. The operating levers are each designed for a two-axial movement and are spatially separate from each other such that the fingers of a hand positioned between the levers can actuate the operating levers without grasping, and can actuate the at least one switch between the operating levers.
DE 10 2005 000 633 A1 has disclosed providing vibrations in the control element and/or the driver's seat as feedback for vehicle states and/or vehicle information. This is haptic feedback of vehicle states and/or vehicle information. When the control element is embodied as a joystick, there is reliable and direct feedback of vehicle states and/or vehicle information by electromagnets generating vibrations, or an electric motor interacting with an unbalanced mass.
Control elements designed as a joystick are known from DE 10 2014 103 988 A1 for controlling commercial vehicles, machines, work functions of commercial vehicles or construction machines and attachments. The use of force feedback is also known for the joysticks. Force feedback is mechanical feedback which is normally achieved by coupled torque of an electric motor with the assistance of a gear unit. Different technical embodiments of the actuating lever of the joystick are known for implementing force feedback.
A key aspect in the operation of an industrial truck is its stability. Variables that influence the stability are the load weight, distance from the load's center of gravity, lifting height and tilt of the mast. In addition to these static variables, there are dynamic processes that have an influence on stability such as braking, reverse acceleration, driving in a curve, etc. A number of different approaches are known for determining stability. In one approach, the force or pressure is measured at different positions of the vehicle. Other approaches such as those in DE 100 15 707 A1, DE 103 04 658 A1 or DE 10 2005 012 004 A1 are based on model-based considerations.
An operating lever for a vehicle or a working machine that has means for generating a resetting force was disclosed in laid-open application DE 197 53 867 A1. A stop is provided for the operating lever, and the resetting force is increased overproportionally depending on the deflection.
An operating lever was disclosed in WO 2016/019 091 A1 that transmits information to the user by an adjustable resetting force and adjustable vibrations.
The object of the invention is to provide a method for operating an industrial truck, as well as an industrial truck that prevents misuse from the standpoint of stability, even in difficult circumstances.